In a heavy saucepan over medium heat combine flour with vegetable oil to make roux. Stir continuously to make sure that mixture does not scorch until dark brown color with nutty aroma is achieved. In heavy stock pot, saute onions, celery, peppers and garlic in peanut oil until vegetables are soft approximately 15 minutes. Add tomatoes, spices, sausage and chicken stock. Slowly add 2/3 to 1 cup of roux 1 tablespoon at a time. When proper thickness, add shrimp and cook until opaque. Lower heat and simmer. Next add crawfish, crabmeat and oysters. Let simmer for another half hour.